Ethanol → Ethyl 3,4-dihydropyrrolo[3,4-b]indole-2(1H)-carboxylate

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Reaction Steps

When N-carbethoxy-3-pyrrolidinone phenylhydrazone was reacted in refluxing ethanol in the presence of various strong acid catalysts such as 85% phosphoric acid, concentrated sulfuric acid and anhydrous zinc chloride, the best yield of 2-carbethoxy- 1,2,3,4-tetrahydropyrrolo[3,4-b]indole obtained was 10% of theory. The above phenylhydrazone (M.P. 138° C.) was obtained by reacting equimolar amounts of phenylhydrazine hydrochloride and N-carbethoxypyrrolidinone in refluxing ethanol. The phenylhydrazone is isolated by neutralizing the cooled reaction mixture with potassium carbonate, diluting with water, filtering and drying.

Provenance & Evidence